Wednesday, April 29, 2009

Cast stone

I had find many products about Natural Stone Slate from some websites such as

kashmir white granite slabs

kashmir white granite slabs price: 2cm slabs: USD:48.00/SQM 3cm slabs: USD:60.00/SQM prices quoted are..

Iran Beige Travertine

Apexstone Amoy Marble & Granite present wide varieties and strict quality controlled natural stone..

And you can see more from gang sawn stone light green marble marble artificial stones quartz viewing stone cut precious stones korea made stones chinese gold quartzite mix color stone mahogany dakota slabs
Cast stone is defined as refined architectural concrete building unit manufactured to simulate natural cut stone, used in unit masonry applications. Cast stone is a masonry product, used as an architectural feature, trim, ornament or facing for buildings or other structures. Cast stone can be made from white and/or grey cements, manufactured or natural sands, carefully selected crushed stone or well graded natural gravels and mineral coloring pigments to achieve the desired color and appearance while maintaining durable physical properties which exceed most natural cut building stones. Cast stone is an excellent replacement for natural cut limestone, brownstone, sandstone, bluestone, granite, slate, coral rock, travertine and other natural building stones.
History

The walled city of Carcassonne
Cast stone has been a prime building material for hundreds of years. The earliest known use of Cast stone dates about to the year 1138 and was seen at Carcassonne, France, the city which contains the finest remains of medieval fortification in Europe. Cast stone was first used extensively in London in the year 1900 and gained widespread acceptance in America in 1920.
One of the earliest developments in the industry was Coade stone, a fired ceramic, but most artificial stone consists of fine cement concrete placed to set in wooden or iron moulds. It was cheaper and more uniform than natural stone, and widely used. In engineering projects, it had the advantage that transporting the bulk materials and casting them near the place of use was cheaper than transporting very large pieces of stone.
A well-known variety was Victoria stone, which is composed of finely crushed Mount Sorrel (Leicestershire) granite and Portland cement, carefully mixed by machinery in the proportions of three to one, and filled into moulds of the required shape. When the blocks are set hard the moulds are loosened and the blocks placed in a solution of silicate of soda for about two weeks for the purpose of indurating and hardening them. Many manufacturers turn out a material that is practically non-porous and is able effectually to resist the corroding influence of sea air or the impure atmosphere of large towns.
Physical properties
Today, cast stone is a Portland cement-based architectural precast concrete product manufactured using high quality fine and coarse aggregate as its primary constituents. Simulated stone, or look-alike products made with alternative ingredients such as gypsum, lightweight products, glass fiber, calcium silicate, stucco and other materials are less durable and not nearly as well time-tested. The use of a high percentage of fine aggregate creates a very smooth, consistent texture for the building elements being cast, resembling natural cut stone. Other ingredients such as chemical admixtures, pozzolans, and pigments also may be added.
Cast stone frequently is produced with a low water-to-cement ratio mixture with a "dry" (or "earth moist") consistency. The mixture is consolidated into a mould using an air-driven tamping device or vibration under pressure, which is much like the formation of natural sedimentary rock. Products manufactured in this manner are referred to as vibrant-dry-tamped (VDT) cast stone. For cast stone mixtures produced with a slumpable consistency mixture, the concrete typically is consolidated using internal or external vibration applied to the production mould.
Over the last decade, new types of admixtures have been developed for VDT concrete products. These new admixtures do not normally work with "wet cast" concrete. These new plasticizers are more efficient than using air-entraining agents to increase compaction in VDT concrete. Some plasticizers have chemical properties that react with the cement to increase ultimate strengths of semi-dry concrete. Another important type of admixture for VDT concrete is integral waterproofing formulas. Tests have shown that some of these integral waterproofing admixtures have improved strength by as much as 20% while reducing the absorption by 40%. The increased strength and reduced absorption results in improved freeze/thaw durability.
On recent commercial testing laboratory results the freeze-thaw for VDT concrete using integral waterproofing admixtures was 0.23% weight loss after 300 cycles. The Cast Stone Institute standard for this product is 5% or less. Admixtures have been used in wet cast concrete for over half a century. Air entraining agents have been the salvation of wet cast concrete as it pertains to its durability. Wet cast concrete with 4% to 6% entrained air normally can withstand numerous freeze-thaw cycles without failing. Other types of admixtures such as water-reducers, super plasticizers and the new self-compacting additives can add to improving the strength and durability of wet cast concrete products. Cast stone products manufactured by the wet cast method...(and so on)

outside wall stone

outside wall stone Here is some of our products : Available Natural Stone Products: 1) Granite,..

You can also see some feature products :

wholesale rough stone red/honey onyx marble discounted quartz slab sea green limestone light transmissive stone natural culture slate red glass stone semi p. stones grey granite paving china artificial stone india blue marble window sill stone granite ribbed stone Wooden Storage Cubes fish tank gravels spain white marble granite and stones l a galaxy muyu stone slabs purple vien sandstone rough turquoise stone

No comments:

Post a Comment